Hyaluronic Acid Binding Domain-Growth Factor Fusion Protein cDNAs and Fusion Proteins for Cartilage Matrix Preservation and Report

ABSTRACT

The present invention provides isolated nucleic acid compounds, amino acids compounds and related materials, along with methods to make and use the compounds. In particular, there are provided gene therapy materials useful for inducing positive physiological responses in tissues, and fusion proteins encoded by the gene therapy materials.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation Application of U.S. application Ser. No. 14/294,305 filed Jun. 3, 2014 which claims priority to U.S. Provisional Application No. 61/830,925, filed on Jun. 4, 2013, the entire disclosure of which is expressly incorporated herein by reference for all purposes.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH

This invention was made with government support under AR047702 awarded by the National Institutes of Health. The government has certain rights in this invention.

SEQUENCE LISTING

The Sequence Listing, filed electronically in ASCII text format and identified as 3619_54880_SEQ_LIST_IURTC-11114.txt, was created on May 29, 2014, is 140,103 bytes in size and is hereby incorporated by reference.

BACKGROUND OF THE INVENTION

Articular cartilage damage is a major cause of disability in the form of arthritis and joint trauma. Because articular cartilage lacks the ability to effectively repair itself, articular cartilage repair is an unsolved clinical problem.

Growth factors, such as insulin-like growth factor-I (IGF-1), promote articular chondrocyte reparative activity. When delivered to articular cartilage as potential therapeutic agents, these factors are limited by rapid elimination from the joint, slower uptake by the articular cartilage containing the target cells, and, when present in the cartilage or repair tissue, are subject to diffusion out of the tissue where it is needed.

Biologic agents are needed that can promote cartilage biosynthesis in vitro and in vivo. A promising candidate for improving articular chondrocyte function is IGF-1. This polypeptide growth factor has been shown to stimulate the synthesis of type-2 collagen and aggrecan, two principle constituents of cartilage matrix, to stimulate the division of articular chondrocytes and to decrease the endogenous catabolic activity of these cells. Therapeutic application of IGF-1 to cartilage repair has been reported in animal models when delivered as a protein, or by gene transfer. However, an unpublished clinical trial of IGF-1 delivery to human knee joints was evidently unsuccessful. A major limitation of current approaches to IGF-1 therapy include: 1) The rapid removal of IGF-1 from the joint through the synovium, 2) the relatively slow diffusion of IGF-1 into the articular cartilage where it can act on the cells, and 3) limited responsiveness of arthritic chondrocytes to the IGF-1. A means of simultaneously providing cells, IGF-1, and of gradual IGF-1 release over time is needed.

The foregoing example of the related art and limitations related therewith are intended to be illustrative and not exclusive. Other limitations of the related art will become apparent to those of skill in the art upon a reading of the specification and a study of the drawings.

SUMMARY OF THE INVENTION

The following embodiments and aspects thereof are described and illustrated in conjunction with systems, tool and methods which are meant to be exemplary and illustrative, not limiting in scope. In various embodiments, one or more of the above described problems have been reduced or eliminated, while other embodiments are directed to other improvements.

The present invention provides isolated nucleic acid molecules comprising a nucleic acid sequence that encodes a fusion protein comprising: a.) a hyaluronic acid-binding domain of a cartilage matrix protein (HAB) operably linked to b.) a conserved region of a growth factor protein (GF), wherein said fusion protein is capable of up-regulating glycosaminoglycan (GAG) expression in chondrocytes.

Also provided are such isolated nucleic acid molecules herein, wherein the nucleic acid molecule further comprises a nucleic acid sequence that encodes at least one signal peptide (SP).

Also provided are such isolated nucleic acid molecules herein, wherein the nucleic acid molecule encodes a fusion protein which further comprises at least one linker sequence.

Also provided are such isolated nucleic acid molecules herein, wherein the nucleic acid molecule encodes a fusion protein which further comprises at least one protease cleavage sequence.

Also provided are such isolated nucleic acid molecules herein, wherein the nucleic acid molecule encodes a fusion protein which further comprises at least one additional functional peptide.

Also provided are such isolated nucleic acid molecules herein, wherein the order of operably-linked elements, 5′ to 3′ is: SP-HAB-GF.

Also provided are such isolated nucleic acid molecules herein, wherein the order of operably-linked elements, 5′ to 3′ is: SP-HAB-GF-additional peptide sequence.

Also provided are such isolated nucleic acid molecules herein, wherein the order of operably-linked elements, 5′ to 3′ is: SP-HAB-linker-GF-additional peptide sequence.

Also provided are such isolated nucleic acid molecules herein, wherein the order of operably-linked elements, 5′ to 3′ is: SP-HAB-linker-protease cleavage sequence-GF-additional peptide sequence.

Also provided are such isolated nucleic acid molecules herein, wherein the SP is selected from the group consisting of: aggrecan signal peptide; CD44 signal peptide; link protein signal peptide; TSG-6 signal peptide; versican signal peptide; and other HA-binding protein signal peptide.

Also provided are such isolated nucleic acid molecules herein, wherein the HAB element comprises a polynucleotide fragment of a nucleotide sequence encoding a protein selected from the group consisting of: aggrecan; CD44; link protein; TSG-6; versican; and other HA-binding proteins.

Also provided are such isolated nucleic acid molecules herein, wherein the linker is selected from the group consisting of: Linker 1: GGSG (SEQ ID NO: 1); Linker 2: GGSGGGSG (SEQ ID NO: 2); Linker 3: GGSGGGSGGGSG (SEQ ID NO: 3); Linker 4: GGGGS (SEQ ID NO: 4); Linker 5: GGGGSGGGGS (SEQ ID NO: 5); Linker 6: GGGGSGGGGSGGGGS (SEQ ID NO: 6); Linker 7: GGSGGS (SEQ ID NO: 7); and Linker 8: VIGHPIDSE (SEQ ID NO: 8).

Also provided are such isolated amino acid molecules herein, further comprising a cleavage site for a protease selected from the group consisting of: enterokinase (EK); Furin; Factor Xa; Matrix metalloproteinase (MMP); and Aggrecanase.

Also provided are such isolated nucleic acid molecules herein, wherein the GF is selected from the group consisting of: IGF-1; BMP2; BMP4; BMP7; FGF2; FGF18; GDF5; TGF-β1; TGF-β3; and other growth factors that influence the target cells.

Also provided are such isolated nucleic acid molecules herein, wherein the additional peptide sequence is selected from the group consisting of: IGF-I signal peptide; and IGF-I E peptide.

Also provided are such polypeptides, wherein the CD44 HAB element is selected from the group consisting of: amino acids 1-132 of SEQ ID NO: 64; amino acids 1-156 of SEQ ID NO: 68; 1-178 of SEQ ID NO: 72; and 1-222 of SEQ ID NO: 76.

Also provided are such isolated nucleic acid molecules herein, wherein the nucleic acid molecule encodes a fusion protein comprising HAB and IGF-1 linked by a number of amino acids selected from the group consisting of: at least about 60 amino acids, at least about 50 amino acids, at least about 40 amino acids, at least about 30 amino acids, at least about 20 amino acids, fewer than 20 amino acids; fewer than 15 amino acids; fewer than 10 amino acids; fewer than 5 amino acids; no amino acids.

Also provided are such isolated nucleic acid molecules herein, wherein the nucleic acid molecule is selected from the group consisting of DNA and RNA.

Also provided are such isolated nucleic acid molecules herein, wherein the nucleic acid molecule comprises:

-   -   a.) one or more signal peptide (SP);     -   b.) one or more hyaluronic acid-binding domain nucleic acid         construct (HAB);     -   c.) one or more linker sequence (linker sequence);     -   d.) one or more protease cleavage sequence (protease cleavage         sequence);     -   e.) one or more conserved region of a growth factor protein         sequence (GF conserved region sequence);     -   f.) one or more additional peptide sequence (additional         peptide); wherein the nucleic acids are operably linked so as to         express a functional fusion protein.

Also provided are plasmids comprising a nucleic acid molecule herein.

Also provided are expression vectors comprising a nucleic acid molecule herein.

Also provided are expression vectors herein, which further comprises at least one regulatory element.

Also provided are expression vectors herein, wherein the regulatory element is selected from the group consisting of: promoter; repressor; enhancer; activator; and transcription factor.

Also provided are expression vectors herein, which is a viral vector.

Also provided are expression vectors herein, which is an adeno-associated virus plasmid (pAAV).

Also provided are cells transformed, transfected or transduced by a vector herein.

Also provided are cells herein, which is a chondrocyte.

Also provided are animal models comprising an expression vector herein.

Also provided are fusion proteins, comprising: a.) at least one hyaluronic acid-binding domain of a cartilage matrix protein (HAB) linked to b.) at least one conserved region of a growth factor protein (GF), wherein said fusion protein is capable of upregulating glycosaminoglycan (GAG) expression in chondrocytes.

Also provided are fusion proteins herein, wherein the fusion protein upregulates GAG expression in chondrocytes by 20-50%, 30-70%, 50-100%, 75-200%, 100-300%, or 200-500%.

Also provided are fusion proteins herein, which further comprise at least one signal peptide (SP).

Also provided are fusion proteins herein, which further comprise at least one linker peptide.

Also provided are fusion proteins herein, which further comprise at least one protease cleavage sequence.

Also provided are fusion proteins herein, which further comprise at least one additional functional peptide.

Also provided are fusion proteins herein, wherein the order of elements, N-terminus to C-terminus is: SP-HAB-GF.

Also provided are fusion proteins herein, wherein the order of elements, N-terminus to C-terminus is: SP-HAB-GF-additional peptide sequence.

Also provided are fusion proteins herein, wherein the order of elements, N-terminus to C-terminus is: SP-HAB-linker-GF-additional peptide sequence.

Also provided are fusion proteins herein, wherein the order of elements, N-terminus to C-terminus is: SP-HAB-linker-protease cleavage sequence-GF-additional peptide sequence.

Also provided are fusion proteins herein, wherein the SP is selected from the group consisting of: aggrecan signal peptide, CD44 signal peptide; link protein signal peptide; TSG-6 signal peptide, versican signal peptide; and other HA-binding protein signal peptide.

Also provided are fusion proteins herein, wherein the HAB is selected from the group consisting of: aggrecan; CD44; link protein; TSG-6; versican; and other HA-binding proteins.

Also provided are fusion proteins herein, wherein the linker is selected from the group consisting of: Linker 1: GGSG (SEQ ID NO: 1); Linker 2: GGSGGGSG (SEQ ID NO: 2); Linker 3: GGSGGGSGGGSG (SEQ ID NO: 3); Linker 4: GGGGS (SEQ ID NO: 4); Linker 5: GGGGSGGGGS (SEQ ID NO: 5); Linker 6: GGGGSGGGGSGGGGS (SEQ ID NO: 6); Linker 7: GGSGGS (SEQ ID NO: 7); and Linker 8: VIGHPIDSE (SEQ ID NO: 8).

Also provided are fusion proteins herein, comprising a protease cleavage site selected from the group consisting of: SEQ ID NO: 9; SEQ ID NO: 10; SEQ ID NO: 11; SEQ ID NO: 12; and SEQ ID NO: 13.

Also provided are fusion proteins herein, wherein the GF is selected from the group consisting of: IGF-1; BMP2; BMP4; BMP7; FGF2; FGF18; GDF5; TGF-β1 and TGF-β3 and other growth factors that influence the target cells.

Also provided are fusion proteins herein, wherein the additional peptide sequence is selected from the group consisting of: IGF-I signal peptide; and IGF-I E peptide.

Also provided are fusion proteins herein, wherein the CD44 HAB element is selected from the group consisting of: CD44(132); CD44(156); CD44(178); and CD44(222).

Also provided are fusion proteins herein, which comprise a number of flanking amino acids to the HAB, wherein the number of flanking amino acids is selected from the group consisting of: 5 amino acids; 10 amino acids; 15 amino acids; 20 amino acids; 25 amino acids; 30 amino acids; 35 amino acids; 40 amino acids; 45 amino acids; 50 amino acids; 55 amino acids; and 60 amino acids.

Also provided are fusion proteins herein, which comprise a number of flanking amino acids to the HAB, wherein the flanking amino acids are at the N terminus of HAB, and wherein the number of flanking amino acids is selected from the group consisting of: 5 amino acids; 10 amino acids; 15 amino acids; 20 amino acids; 25 amino acids; 30 amino acids; 35 amino acids; 40 amino acids; 45 amino acids; 50 amino acids; 55 amino acids; and 60 amino acids.

Also provided are fusion proteins herein, which comprise a number of flanking amino acids to the HAB, wherein the flanking amino acids are at the C terminus of HAB, and wherein the number of flanking amino acids is selected from the group consisting of: 5 amino acids; 10 amino acids; 15 amino acids; 20 amino acids; 25 amino acids; 30 amino acids; 35 amino acids; 40 amino acids; 45 amino acids; 50 amino acids; 55 amino acids; and 60 amino acids.

Also provided are compositions comprising a nucleic acid molecule herein and a pharmaceutically-acceptable carrier.

Also provided are compositions comprising a fusion protein herein and a pharmaceutically-acceptable carrier.

Also provided are methods of producing a fusion protein comprising expressing a nucleic acid molecule herein in at least one cell.

Also provided are methods herein, wherein the cell is selected from the group consisting of prokaryotic cell and eukaryotic cell.

Also provided are methods herein, wherein the cell is a chondrocyte.

Also provided are methods to upregulate glycosaminoglycan expression in at least one chondrocyte, comprising expressing a nucleic acid molecule herein in at least one chondrocyte.

Also provided are methods to increase GF diffusion rates to the articular cartilage of a subject, comprising expressing a nucleic acid molecule herein in at least one chondrocyte in at least one joint of a subject and increasing GF diffusion rates to the articular cartilage of the subject.

Also provided are methods to increase responsiveness rates of arthritic chondrocytes to GF in a subject, comprising expressing a nucleic acid molecule herein in at least one chondrocyte in at least one arthritic joint of a subject and increasing responsiveness rates of arthritic chondrocytes to GF in the subject.

Also provided are methods to treat cartilage matrix protein-related pathology in a subject, comprising expressing a nucleic acid molecule herein in at least one chondrocyte in the cartilage matrix of a subject with cartilage matrix protein-related pathology and treating cartilage matrix protein-related pathology in the subject.

Also provided are methods herein, wherein the cartilage matrix protein-related pathology is selected from the group consisting of: joint stiffness; degenerative disease; facet disease; osteoarthritis; and rheumatoid arthritis.

Also provided are methods to ameliorating joint pain or intervertebral disc pain in a subject, comprising expressing a nucleic acid molecule herein in at least one painful joint or painful intervertebral disc of a subject and ameliorating joint pain or intervertebral disc pain in the subject.

Also provided are methods to ameliorate the symptoms of joint injury or intervertebral disc injury in a subject, comprising expressing a nucleic acid molecule herein in at least one injured joint or injured intervertebral disc of a subject and ameliorating the symptoms of joint injury or intervertebral disc injury in the subject.

Also provided are methods herein, wherein the cartilage matrix, joint, and/or intervetebral disc injury is selected from the group consisting of: traumatic injury; surgical injury; degenerative disease; developmental defect; and work injury.

Also provided are methods to increase sports performance in an athlete, comprising expressing a nucleic acid molecule herein in at least one joint or intervertebral disc of an athlete and increasing sports performance in the athlete.

Also provided are methods herein, wherein the sports performance is selected from the group consisting of: increased speed; increased endurance; increased weight-lifting ability; increased flexibility; increased strength; increased resistance to impact; increased concentration; and increased career length.

Also provided are methods herein, wherein the subject or athlete is a mammal selected from the group consisting of: laboratory animal; companion animal; draft animal; meat animal; and human.

Also provided are methods herein, wherein the subject or athlete is a mammal selected from the group consisting of: cat; dog; horse; bovine; and human.

Also provided are methods herein, wherein the cartilage matrix is selected from the group consisting of: toe; ankle; knee; hip; spine; shoulder; neck; elbow; wrist; fingers; and thumb.

Also provided are methods herein, wherein the cartilage matrix is selected from the group consisting of: cartilage of the nose; and cartilage of the ear.

Also provided are methods herein, wherein the cartilage matrix is at least one intervertebral disc.

Also provided are methods to upregulate glycosaminoglycan expression in at least one chondrocyte, comprising introducing a fusion protein herein to at least one chondrocyte.

Also provided are methods to decrease GF removal rates from the joint synovium or intervertebral disc synovium of a subject, comprising introducing a fusion protein herein in at least one joint or intevertebral disc of a subject and decreasing GF removal rate from the joint synovium or intervertebral disc of the subject.

Also provided are methods to increase responsiveness rates of chondrocytes to GF in a subject, comprising introducing a fusion protein herein in at least one chondrocyte of a subject and increasing responsiveness rates of chondrocytes to GF in the subject.

Also provided are methods to ameliorate cartilage matrix protein-related pathology in a subject, comprising introducing a fusion protein herein in the cartilage matrix of a subject with cartilage matrix protein-related pathology and ameliorating cartilage matrix protein-related pathology in the subject.

Also provided are method herein, wherein the cartilage matrix protein-related pathology is selected from the group consisting of: joint stiffness; degenerative joint disease; facet disease; osteoarthritis; and rheumatoid arthritis.

Also provided are methods to ameliorate joint pain or intervertebral disc pain in a subject, comprising introducing a fusion protein herein in at least one painful joint or painful intervertebral disc of a subject and ameliorating joint pain or intervetebral disc pain in the subject.

Also provided are methods to ameliorate the symptoms of joint or intervertebral disc injury in a subject, comprising introducing a fusion protein herein in at least one injured joint or intervertebral disc of a subject and ameliorating the symptoms of joint or intervertebral disc injury in the subject.

Also provided are methods herein, wherein the joint or intervertebral disc injury is selected from the group consisting of: traumatic injury; surgical injury; degenerative disease; developmental defect; and work injury.

Also provided are methods to increase sports performance in an athlete, comprising introducing a fusion protein herein in at least one joint or intervertebral disc of an athlete and increasing sports performance in the athlete.

Also provided are methods herein, wherein the sports performance is selected from the group consisting of: increased speed; increased endurance; increased weight-lifting ability; increased flexibility; increased strength; increased resistance to impact; increased concentration; and increased career length.

Also provided are methods herein, wherein the subject or athlete is a mammal selected from the group consisting of: laboratory animal; companion animal; draft animal; meat animal; and human.

Also provided are methods herein, wherein the subject or athlete is a mammal selected from the group consisting of: cat; dog; horse; bovine; and human.

Also provided are methods herein, wherein the cartilage matrix is selected from the group consisting of: toe; ankle; knee; hip; spine; shoulder; neck; elbow; wrist; fingers; and thumb.

Also provided are methods herein, wherein the cartilage matrix is selected from the group consisting of: cartilage of the nose; and cartilage of the ear.

Also provided are methods herein, wherein the cartilage matrix is at least one intervertebral disc.

Also provided is the invention as shown and described herein.

The term “joint cavity,” “joint space,” and “joint capsule” refer to a hollow or fluid-filled place or depression in the place of union or junction between two or more bones of the skeleton, including the space of a synovial joint, enclosed by the synovial membrane and articular cartilages.

The terms “treat”, “treatment,” and “treating” and/or “ameliorating” include pathology reduction, reduction in symptoms, preventative (e.g., prophylactic) and palliative care.

In addition to the exemplary aspects and embodiments described above, further aspects and embodiments will become apparent by reference to the accompanying drawings forming a part of this specification wherein like reference characters designate corresponding parts in the several views.

BRIEF DESCRIPTION OF THE FIGURES

The patent or application file may contain one or more drawings executed in color and/or one or more photographs. Copies of this patent or patent application publication with color drawing(s) and/or photograph(s) will be provided by the Patent Office upon request and payment of the necessary fee.

FIGS. 1A-1B. Schematic illustration of three HA binding proteins (aggrecan, link protein and versican) and human IGF-I (FIG. 1A), and HAB-IGF-I fusion proteins (FIG. 1B).

FIG. 1A: Human aggrecan and versican precursors each contains a signal peptide (SP) and G1 domain thereafter, which is responsible for aggrecan and versican binding to HA. Link protein consists of a signal peptide and a mature link protein peptide, which is homologous to the G1 domains of aggrecan and versican and also functions to bind to HA. Human IGF-I precursor consists of a signal peptide (aa 1-48), mature IGF-I peptide (aa 49-118) and E peptide (aa 119-153).

FIG. 1B: HAB-IGF-I fusion proteins (AG1-IGF-I, LP-IGF-I and VG1-IGF-I) were made up of human HA binding protein (aggrecan, link protein and versican) and human IGF-I, each box representing a native domain or region of human aggrecan, link protein and versican. HAB-IGF-I fusion protein AG1-IGF-I was created by fusion of aggrecan (aa 1-357) to IGF-I (aa 49-153), HAB-IGF-I fusion protein LP-IGF-I was created by fusion of link protein (aa 1-354) to IGF-I (aa 49-153) and HAB-IGF-I fusion protein VG1-IGF-I was created by fusion of versican (aa 1-363) to IGF-I (aa 49-153).

FIGS. 2A-2B. Schematic illustration of human HA receptor CD44 and human IGF-I (FIG. 2A), and CD44-IGF-I fusion proteins (FIG. 2B).

FIG. 2A: Human CD44 precursor consists of a 20 aa signal peptide (SP), an extracellular region from AA21 to AA268, a 20 aa transmembrane region (TM) and a 73 aa of the intracellular region at c-terminal. The extracellular region from AA21 to AA268 contains the HA-binding domain, which is responsible for the binding of CD44 to HA. The human IGF-I precursor consists of a signal peptide (aa 1-48), mature IGF-I peptide (aa 49-118) and E peptide (aa 119-153).

FIG. 2B: CD44-IGF-I fusion proteins were made up of human CD44 and human IGF-I, each box representing a native domain or region of human CD44 and human IGF-I. CD44(132)-IGF-I was created by fusion of CD44(aa 1-132) to IGF-I(aa 49-153), CD44(156)-IGF-I was created by fusion of CD44 (aa 1-156) to IGF-I(aa 49-153), CD44(178)-IGF-I was created by fusion of CD44(aa 1-178) to IGF-I(aa 49-153), CD44(222)-IGF-I was created by fusion of CD44(aa 1-222) to IGF-I(aa 49-153).

FIGS. 3A-3C. Schematic illustration of human HA receptor CD44 and human IGF-I (FIG. 3A), CD44(178)-IGF-I fusion protein (FIG. 3B) and CD44(178)-IGF-I fusion protein with linker (FIG. 3C).

FIG. 3A: Human CD44 precursor consists of a 20 aa signal peptide (SP), an extracellular region from AA21 to AA268, a 20 aa transmembrane region (TM) and a 73 aa of the intracellular region at c-terminal. The extracellular region from AA21 to AA268 contains the HA-binding domain, which is responsible for the binding of CD44 to HA. The human IGF-I precursor consists of a signal peptide (aa 1-48), mature IGF-I peptide (aa 49-118) and E peptide (aa 119-153).

FIG. 3B: CD44(178)-IGF-I fusion protein was created by fusion of CD44 (aa 1-178) to IGF-I(aa 49-153).

FIG. 3C: CD44(178)-IGF-I fusion protein with linker was created by inserting a linker sequence after the sequence of CD44(178) and before the sequence of IGF-I in CD44(178)-IGF-I. FIG. 3C discloses SEQ ID NOS 1-8, respectively, in order of appearance.

FIGS. 4A-4C. Schematic illustration of human versican and human IGF-I (FIG. 4A), VG1-IGF-I fusion protein (FIG. 4B) and VG1-IGF-I fusion proteins with a cleavage site (FIG. 4C).

FIG. 4A) Human versican precursor contains G1 domain (VG1). It is responsible for versican binding to HA. The human IGF-I precursor consists of a signal peptide (aa 1-48), mature IGF-I peptide (aa 49-118) and E peptide (aa 119-153).

FIG. 4B) VG1-IGF-I was created by fusion of versican (aa 1-363) to IGF-I(aa 49-153).

FIG. 4C) VG1-IGF-I fusion protein with protease cleavage site was created by inserting the designated protease cleavage site sequences after the sequence of VG1 and before the sequence of IGF-I in VG1-IGF-I. The triangle (▾) indicates the point of cleavage within the cleavage site sequence. FIG. 4C discloses SEQ ID NOS 9-13, respectively, in order of appearance.

Before explaining the disclosed embodiment of the present invention in detail, it is to be understood that the invention is not limited in its application to the details of the particular arrangement shown, since the invention is capable of other embodiments. Exemplary embodiments are illustrated in referenced figures of the drawings. It is intended that the embodiments and figures disclosed herein are to be considered illustrative rather than limiting. Also, the terminology used herein is for the purpose of description and not of limitation.

DETAILED DESCRIPTION OF THE INVENTION

Described are a set of related but distinct nucleic acid molecules that encode fusion proteins comprised by a hyaluronic acid-binding domain and insulin-like growth factor-I. Cells to which such nucleic acid molecules are transferred manufacture the fusion protein. Using a gene therapy approach, the fusion protein is made by the chondrocytes themselves. The nucleic acid molecules are designed to enable their protein products to 1) remain within the articular cartilage and/or repair tissue by matrix hyaluronic acid (HA) binding to the fusion protein's hyaluronic acid-binding domain and 2) stimulate chondrocyte reparative activity by insulin-like growth factor-I (IGF-1) binding to its cell surface receptors.

In addition, by putting a protease cleavage site between the HA tags and IGF-1, the binding of the HA to the cartilage matrix may be regulated. Further, a sustained release formulation is contemplated herein. The present invention may also be used to release growth factor (GF) in other organs, such as by creating an HA scaffolding in an area of the body so that the GF can be concentrated in one place and released as needed.

An important aspect of embodiments of the present invention is the retention of the molecule within a tissue when delivered as a protein. Further, those tissues that are deficient in matrix elements, for example—if it had already lost constituents, are particularly influenced by such fusion proteins. Without being bound by any particular theory, the fusion proteins facilitate the ability of the growth factor to enter the tissue.

In addition, the fusion protein, when purified from the conditioned medium of producer cells carrying the fusion protein nucleic acid molecule(s), may be used as a therapeutic agent using any of a variety of available protein delivery methods.

In one embodiment, there are provided DNA constructs encoding fusion proteins. The constructs contain the coding region for the mature form of insulin-like 1 (IGF-1). The constructs contain the coding region of at least one cartilage matrix protein hyaluronic acid-binding domain (HAB). The constructs may optionally contain signal peptide and carboxy-terminal extension peptide (E peptide). Vectors containing these cDNA constructs are designed to be transferred into target cells, enabling the cells to produce the encoded fusion proteins and provide local delivery of IGF-1 for tissue repair.

In another embodiment, vectors containing the DNA constructs are designed to be transferred into cultured cells and the fusion protein is recovered from the conditioned media. Examples of cell lines useful for this embodiment include Chinese Hamster Ovary (CHO) cells and HEK-293 cells Human Embryonic Kidney 293 (HEK-293) cells. The fusion protein is then purified, combined with a pharmaceutically acceptable excipient, and formulated into a therapeutically effective dose.

EXAMPLES Example 1. Materials and Methods

Fusion Proteins

The nucleic acid sequences encoding the described proteins and chimeric nucleic acid sequences encoding fusion proteins may be constructed. The chimeric nucleic acid molecules may be prepared with sections encoding a linking peptide connecting the protein portions of the encoded fusion protein. Optionally, the peptide linker may be selected to include residues imparting stearic flexibility in order to enhance the function of the fusion protein.

Fusion Protein Linkers

The components of the fusion proteins may be operatively linked directly one to the other. The two protein components of the fusion protein may be directly linked via an amino terminus to carboxy terminus peptide bond.

Alternatively, one or more linker molecules connect the two portions of the fusion protein. The linker molecule allows the two portions of the fusion protein increased stearic freedom. In one embodiment, the linkers are peptide linkers. Peptides for linking protein chains are known to the art (Huston et al., 1993, Immunotechnology, ed. by J. Gosling et al., 47-60; Huston et al., Molecular Design and Modeling: Concepts and Applications, Part B, ed. J. J. Langone, Methods in Enzymology 203:46-88; Chaudhary et al, 1989, Nature 339:394-397). For example, a DNA construct may be prepared by recombinant methods or by polymerase chain reaction.

Examples of linkers include, for example, the linkers of FIG. 3C. Linker 1: GGSG; Linker 2: GGSGGGSG; Linker 3: GGSGGGSGGGSG; Linker 4: GGGGS; Linker 5: GGGGSGGGGS; Linker 6: GGGGSGGGGSGGGGS; Linker 7: GGSGGS; and Linker 8: VIGHPIDSE (SEQ ID NOS 1-8, respectively, in order of appearance).

The DNA construct sequentially, 5′ to 3′, encodes a first part of a fusion protein, then a peptide linker region, followed by a second part of a fusion protein as a single open reading frame, flanked by regulatory elements suitable for expressing the encoded fusion protein in a host cell. The peptide linker according to the invention may optionally include serine, glycine or other residues that will act as “molecular hinges” to allow greater stearic freedom.

The peptide linker may be encoded by the chimeric nucleic acid molecule, protein parts may be prepared separately and the fusion protein assembled by peptide chemical methods.

In another alternative, the linker molecule may be comprised of peptide and non-peptide polymers or may be exclusively non-peptide in composition. A wide variety of organic linkers are known in the art. For example, polyalkane polymers (e.g., —(CH₂)_(n)—) may be readily linked by well known methods to thiol groups on sulfhydral containing amino acids.

Vectors and Promoters

The present invention further relates to vectors expressing the fusion proteins according to the invention. The vectors may be selected from any suitable vectors for inserting nucleic acid molecules into human host cells. The vectors may be deoxyribonucleic acid) (“DNA”) vectors such as plasmids, adenovirus or even naked DNA inserted directly into cells to be treated by art known methods. The vectors may also be ribonucleic acid (“RNA”) vectors, such as safe strains of the retroviruses.

Methods for the insertion of nucleic acid molecular fragments into a vector, as described, for example, in Maniatis, T., Fritsch, E. F., and Sambrook, J. (1989): Molecular Cloning (A Laboratory Manual), Cold Spring Harbor Laboratory, Cold Spring Harbor, N.Y.; and Ausubel, F. M., Brent, R., Kingston, R. E., Moore, D. D., Seidman, J. G., Smith, J. A., and Struhl, K. (1992): Current Protocols in Molecular Biology, John Wiley & Sons, New York, may be used to construct fusion protein-encoding expression vectors consisting of appropriate transcriptional/translational control signals. These methods may include in vitro DNA recombinant and synthetic techniques and in vivo genetic recombination. Expression of a nucleic acid sequence encoding the fusion proteins may be regulated by a second nucleic acid sequence so that the fusion protein is expressed in a host infected or transfected with the recombinant chimeric nucleic acid molecule. For example, expression of the fusion proteins may be controlled by a selected promoter/enhancer element. The promoter activation may be tissue specific or inducible by a metabolic product or administered substance.

Promoters/enhancers which may be used to control the fusion protein gene expression include, but are not limited to, the native IGF-1 or EGF promoter, the cytomegalovirus (CMV) promoter/enhancer (Karasuyama, H., et al., 1989, J. Exp. Med., 169:13), the human β-actin promoter (Gunning, et al., 1987, Proc. Natl. Acad. Sci. USA, 84:4831-4835), the glucocorticoid-inducible promoter present in the mouse mammary tumor virus long terminal repeat (MMTV LTR) (Klessig, D. F., et al., 1984, Mol. Cell Biol., 4:1354-1362), the long terminal repeat sequences of Moloney murine leukemia virus (MuLV LTR) (Weiss, R., et al., 1985, RNA Tumor Viruses, Cold Spring Harbor Laboratory, Cold Spring Harbor, N.Y.), the SV40 early region promoter (Bernoist and Chambon, 1981, Nature 290:304-310), the promoter contained in the 3′ long terminal repeat of Rous sarcoma virus (RSV) (Yamamoto et al., 1980, Cell 22:787-797), the herpes simplex virus (HSV) thymidine kinase promoter/enhancer (Wagner et al., 1981, Proc. Natl. Acad. Sci. U.S.A. 78:1441-1445), the regulatory sequences of the metallothionein gene (Brinster et al., 1982, Nature 296:39-42), the adenovirus promoter (Yamada et al., 1985, Proc. Natl. Acad. Sci. U.S.A. 82(11):3567-71), and the herpes simplex virus LAT promoter (Wolfe, J. H., et al., 1992, Nature Genetics, 1:379-384).

Expression vectors compatible with mammalian host cells for use in genetic therapy of cells, include, but are not limited to: plasmids, retroviral vectors, adenovirus vectors, herpes viral vectors, poxvirus vectors and non-replicative avipox viruses, as disclosed, for example, by U.S. Pat. No. 5,174,993. The viral vectors may be suitably modified for safety and modified to be non-replicative in human host cells.

Assays for Chondrocyte-Stimulating Activity

The effectiveness of the fusion proteins herein may be ascertained according to the present examples.

Treatment Methods

The present invention is also directed to methods of ameliorating joint and chondrocyte-associated maladies in any mammal, including laboratory animals, companion animals, draft animals, meat animals, and humans. For instance, the present invention may be used to treat joint disease, injury (surgical or accident), pain, structural defects, or to increase sports performance. In particular, dogs, cats, horses, and humans would be treatable with the compositions and methods of the present invention. Methods of treatment include the direct introduction of the chimeric nucleic acid into the cells of the subject to be treated. Proteins may be introduced to the subject directly.

Alternatively, the methods of treatment include the ex vivo treatment of cells, e.g., chondrocytes that have been removed from a subject's body, followed by the reintroduction of the treated cells into the subject. The ex vivo treatment can be conducted with the fusion protein according to the invention, in order to affect the IGF-1 functionality in the treated tissue. In addition, the ex vivo treatment can be conducted with the chimeric nucleic acid molecules according to the invention, in order that the reintroduced cells will continue to affect IGF-1 functionality after reintroduction.

In another embodiment, vectors according to the invention can be applied to the skin and internal organs by suspension in appropriate physiological carriers.

For example, a physiologically appropriate solution containing an effective concentration of active vectors can be administered topically, interarticularly, intraocularly, parenterally, orally, intranasally, intravenously, intramuscularly, subcutaneously or by any other effective means. In particular, the vector may be directly injected into a target tissue by a needle in amounts effective to treat the cells of the target tissue. Alternatively, a body cavity or tissue can receive a physiologically appropriate composition (e.g., a solution such as a saline or phosphate buffer, a suspension, or an emulsion, which is sterile except for the vector) containing an effective concentration of active vectors via direct injection with a needle or via a catheter or other delivery tube placed into the afflicted tissue. Any effective imaging device such as X-ray, sonogram, or fiberoptic visualization system may be used to locate the target area and guide the needle or other administration device.

In another alternative, a physiologically appropriate solution containing an effective concentration of active vectors can be administered systemically into the blood circulation to treat cells or tissues which cannot be directly reached or anatomically isolated.

In yet another alternative, target cells can be treated by introducing a fusion protein according to the invention into the cells. For example, liposomes are artificial membrane vesicles that are available to deliver drugs, proteins, and plasmid vectors both in vitro or in vivo (Mannino, R. J. et al., 1988, Biotechniques, 6:682-690) into target cells (Newton and Huestis, Biochemistry, 1988, 27: 4655-4659; Tanswell, A. K. et al., 1990, Biochemica et Biophysica Acta, 1044:269-274; and Ceccoll, J. et al. Journal of Investigative Dermatology, 1989, 93:190-194). Thus, fusion protein can be encapsulated at high efficiency with liposome vesicles and delivered into mammalian cells in vitro or in vivo.

Liposome-encapsulated fusion protein may be administered topically, intraocularly, parenterally, intranasally, intratracheally, intrabronchially, intramuscularly, subcutaneously or by any other effective means at a dose efficacious to treat the injured tissue or abnormal cells of the target. The liposomes may be administered in any physiologically appropriate composition containing an effective concentration of encapsulated fusion protein.

An effective concentration of vector or fusion protein may be determined by the ordinary artisan, for example, by screening chimeric nucleic acid vectors encoding fusion protein, or a fusion protein, in a chondrocyte assay system as described herein.

cDNA constructs encoding the present fusion proteins are described in the examples. The human IGF-1 cDNA sequence, including the coding sequence for the mature peptide, with and without the E-peptide were linked to the cDNA sequence encoding the hyaluronic acid-binding domain of cartilage matrix protein (HAB) with and without additional upstream cDNA sequences. When these gene sequences are placed into a vector and transferred into articular chondrocytes, the fusion protein is produced by the cells. The fusion protein is designed to bind to the hyaluronic acid-like molecules present in the tissue matrix that surrounds articular chondrocytes in vivo and during culture in vitro. Because this binding is reversible, the IGF-1 will be released over time. The significance of this approach is that it achieves local IGF-1 delivery over time in the presence of a responsive cell population.

The gene sequences, when expressed by chondrocytes, produce fusion proteins with superior IGF-1 attributes. When the fusion protein is secreted from the chondrocytes, the secreted fusion protein acts upon the cells that produced it and neighboring cells to stimulate cell division, the production of new matrix, and to inhibit cartilage degradation. The compositions are preferably administered locally, preferably by an instrument of injecting liquids into a joint cavity according to conventional methods. In one embodiment of the present method, the solution is directly injected via a syringe needle into the joint space (including connective tissue and synovial) of the patient. The size of the syringe needle is determined by the health professional administering the solution and the amount of solution to be injected into joint space of the patient. Preferably, the syringe is capable of containing at least 0.1 cc of liquid and administering the liquid percutaneously into the joint space of the patient via a syringe needle.

The typical volumes of solution injected into joint space of the patient ranges from 0.1 cc to 10 cc of solution per administration, depending on the size of the joint being treated. Preferably, the solution volume is ranges between 0.5 cc to 5 cc of solution and most preferably, the volume is lcc to 5 cc of solution.

The treatment may optionally include administration of an anesthetic/anti-inflammatory component of the solution dosage typically comprises at least one anesthetic that preferably has a volume that is between 20% to 60% of the total solution volume of each solution dosage. The anti-inflammatory component of the solution dosage may optionally comprise corticosteroids, including, optionally, two corticosteroids, each corticosteroid preferably having a volume that is between 10% to 50% of the total solution volume of each solution dosage.

The anesthetic component of the solution of the present method is selected based on the desired duration of pain relief provided to the painful (arthritic) or connective tissue target of the patient. Exemplary anesthetic compounds include procaine hydrochloride (“Procaine”).

The corticosteroids components are selected from the group consisting of Betamethasone, Methylprednisolone acetate (“Depomedrol”), Cortisone acetate, Dexamethasone, Hydrocortisone, Methylprednisolone, Prednisolone, Prednisolone sodium phosphate, and Prednisone. In one embodiment of the present method corticosteroids component includes a mixture of Dexamethasone and Depomedrol. In one embodiment of the method the anesthetic is buffered.

The needle of the syringe needle of the present method is selected based on the size of the joint space of the patient. In one embodiment of the present method the needle is a hypodermic needle, preferably an arthroscopic needle, but may be other types of needles depending on the application including non-arthroscopic needles. Preferably, the present method provides for needle gauges in the range of between 22 and 25 gauge and from ¾ inch to 1½ inches in length.

Further, the treatment solution is injected into the joint. Preferably, this is done by inserting the syringe needle through the treated topical skin area and then slowly guiding the needle of the syringe needle into the synovia capsule of the target joint. Depending upon the joint or target space capacity, preferably 10 ml or less of the present treatment composition is introduced slowly into the joint capsule.

Further, the treatment may be repeated periodically. Repeat injections may be administered in 1, 5, 7, 10, 20, 30 day or yearly intervals after the first injection. The solution can be mixed in a separate container prior to be loaded into a syringe or they can be mixed in the syringe directly prior to administration.

Example 2. Creation of Hyaluronic Acid Binding—Insulin-Like Growth Factor I Fusion Protein cDNA Constructs

Three cDNAs were created, encoding three hyaluronic acid-binding domain (HAB)—insulin-like growth factor I (IGF-I) fusion proteins (HAB-IGF-I) by coupling the sequence encoding IGF-I with those encoding a hyaluronic acid binding region derived from three cartilage matrix proteins. These regions include 1) the aggrecan G1 domain (AG1), 2) the versican G1 domain (VG1) and 3) link protein (LP). The resulting fusion proteins are designated AG1-IGF-I, VG1-IGF-I, and LP-IGF-I respectively (FIG. 1B). Further, the encoded fusion proteins were created by transferring the cDNAs into producer cells and the selected therapeutic target cells, articular chondrocytes.

To facilitate the HAB-IGF-I constructs to be used for human therapeutic purposes, the DNA constructs encoding all the HAB-IGF-I fusion proteins were generated from native human matrix protein gene sequences and the native human IGF-I gene sequence (Accession number: X57025) and were designed to include signal peptides.

All the constructs described and illustrated in FIG. 1B were created using specifically designed primers by polymerase chain reaction (Table 4).

As shown in FIG. 1A, Aggrecan has two globular structural domains (G1 and G2) near the N-terminal end and one globular domain (G3) at the C-terminal end, separated by a large extended domain modified with glycosaminoglycans. The two main modifier moieties are arranged into distinct regions, a chondroitin sulfate (CS) and a keratan sulfate (KS) region.

Example 3. Production of Fusion Proteins and Demonstration of Fusion Protein Integrity

To promote articular cartilage preservation or repair using these fusion proteins as therapeutic agents, it is necessary to have a production source for the proteins. A method of production employs the fusion protein-encoding cDNAs described above and a non-viral (plasmid) vector that the inventors developed previously, Shi et al., Effect of Transfection Strategy on Growth Factor Overexpression by Articular Chondrocytes, J. of Orthopaedic Research, January 2010, hereby incorporated by reference. The cDNAs were inserted into the vector and used to transfect HEK 293 cells (Stratagene). The HEK 293 cells then use these inserted transgenes to synthesize the HAB-IGF-I fusion proteins. On day 3 after transfection conditioned medium was collected for measurement of HAB-IGF-I fusion proteins produced as transgene products by the HEK 293 cells. The production and integrity of these proteins was confirmed by IGF-I ELISA (R&D Systems) and a HA-binding functional ELISA.

It was found that pAAV-VG-IGF-I transfected cells produced a high level of IGF-I (1939 ng/ml), pAAV-AG1-IGF-I transfected cells produced 865 ng/ml of IGF-I, and pAAV-LP-IGF-I transfected cells only produced 5 ng/ml of IGF-I. HA-binding functional ELISA data demonstrated that the VG-IGF-I and the AG1-IGF-I fusion proteins successfully attached to hyaluronic acid, and AG1 or VG1 and IGF-I are linked together.

Example 4. Demonstration of Bioactivity of Transferred HAB-IGF-I Genes in Articular Chondrocytes

To promote articular cartilage preservation or repair using the fusion protein cDNAs as agents for gene therapy, the transgenes must stimulate reparative activity by their host cells. To test this capability, primary bovine articular chondrocytes were transfected and cultured for 5 days. On day 5, the chondrocytes were collected and used to measure biosynthesis of cell-associated matrix molecules. An index of articular chondrocyte reparative activity is the production of glycosaminoglycan (GAG). GAG is an essential component of articular cartilage. It is produced by articular chondrocytes incorporated into their surrounding matrix.

Chondrocytes transfected with pAAV-VG1-IGF-I produced a high level of GAG (71.4±3.3 ug/well), pAAV-AG1-IGF-I transfected cells produced 65.5±0.3 ug/well of GAG, and pAAV-LP-IGF-I transfected cells produced 42.4±0.6 ug/well of GAG.

Example 5. CD44-IGF-I Constructs

Four different constructs of CD44-IGF-I were generated: 1) CD44(132)-IGF-I (SEQ ID NO: 64), 2) CD44(156)-IGF-I (SEQ ID NO: 68), 3) CD44(178)-IGF-I (SEQ ID NO: 72), and 4) CD44(222)-IGF-I (SEQ ID NO: 76). Each construct was separately delivered to bovine chondrocytes using a pAAV-based vector. The empty vector, pAAV-MCS, was used as a control. The conditioned medium was harvested on day 2 after transfection. The conditioned medium was analyzed by both IGF-I ELISA and HA-binding functional ELISA. Different constructs generated dramatically different production of CD44-IGF-I fusion protein in chondrocytes. Construct CD44(156)-IGF-I generated the least amount of fusion protein (13.50 ng/ml) while construct CD44(178)-IGF-I produced the highest amount of fusion protein (289.51 ng/ml), 21.4 fold higher than that of the construct CD44(156)-IGF-I. HA-binding functional ELISA showed that the fusion protein from construct CD44(178)-IGF-I in chondrocytes binds to HA, and CD44(178) and IGF-I are linked together. HA-binding activity was not detectable in the conditioned medium from the chondrocytes transfected by construct CD44(132)-IGF-I, CD44(156)-IGF-I or CD44(222)-IGF-I. Low production of CD44-IGF-I fusion protein in chondoocytes transfected by CD44(132)-IGF-I or CD44(156)-IGF-I interfered with HA-binding activity detection in the condition medium (Table 1).

TABLE 1 Production and HA-binding activity of CD44-IGF-I fusion protein Arbitrary unit IGF-I (ng/ml) (HA-binding (IGF-I ELISA) functional ELISA) Control 0.00 0.00 CD44(132)-IGF-I 19.95 0.00 CD44(156)-IGF-I 13.50 0.00 CD44(178)-IGF-I 289.51 1.70 CD44(222)-IGF-I 172.91 0.00

To improve the HA-binding activity of CD44(178)-IGF-I, nine different constructs were generated, each containing a different linker between CD44(178) and IGF-I, using pAAV-CD44(178)-IGF-I as a template and QuickChange Lighting Site-Directed Mutagenesis Kit (Stratagene). Each construct was separately delivered to bovine chondrocytes using a pAAV vector. The original construct, CD44(178)-IGF-I, in the pAAV vector was included for comparison. The conditioned medium was harvested on day 2 after transfection. The conditioned medium was analyzed by both IGF-I ELISA and HA-binding functional ELISA. Different linkers have varied effects on the fusion protein production and HA-binding activity. Compared to the original construct, CD44(178)-IGF-I, the insertion of Linker 8 increases the fusion protein production and HA-binding activity by 1.7 fold and 2.9 fold respectively (Table 2).

TABLE 2 Production and HA-binding activity of CD44-IGF-I fusion protein with or without a linker Arbitrary unit IGF-I (ng/ml) (HA-binding (IGF-I ELISA) functional ELISA) CD44(178)-IGF-I 278.77 1.56 CD44(178)-Linker 1-IGF-I 278.20 0.77 CD44(178)-Linker 2-IGF-I 236.56 0.99 CD44(178)-Linker 3-IGF-I 144.40 0.33 CD44(178)-Linker 4-IGF-I 271.98 1.11 CD44(178)-Linker 5-IGF-I 267.40 0.21 CD44(178)-Linker 6-IGF-I 240.64 0.40 CD44(178)-Linker 7-IGF-I 343.39 0.30 CD44(178)-Linker 8-IGF-I 463.64 4.47

Example 6. Protease Cleavage Site Constructs

Constructs were generated, each containing a different specific protease cleavage site between VG1 and IGF-I, using pAAV-VG1-IGF-I as a template and QuickChange Lighting Site-Directed Mutagenesis Kit (Stratagene). The resulting constructs and the original construct were delivered to bovine chondrocytes using a pAAV-based vector. The conditioned medium was harvested on day 2 after transfection. The conditioned medium was analyzed by IGF-I ELISA and HA-binding functional ELISA respectively. The constructs with a protease cleavage site generated similar amounts of fusion protein and the resulting fusion proteins had similar HA-binding activity (Table 3), compared with the original construct VG1-IGF-I (Table 1). These VG1 fusion proteins with protease cleavage site are assessed to examine specific proteases cleavage efficiency and to measure the activity of the released growth factor. This method can be applied to aggrecan, CD44, and other HA-binding domains, and other growth factors.

TABLE 3 Production and HA-binding activity of CD44-IGF-I fusion protein Arbitrary unit IGF-I (ng/ml) (HA binding (IGF-I ELISA) functional ELISA) Control 0.00 0.00 VG1-I1 299.03 199.26 VG1-EK-IGF-I 358.97 249.86 VG1-Furin-IGF-I 221.79 228.85 VG1-Xa-IGF-I 312.21 256.90

A depiction of a fusion protein with a cleavage site is shown in FIG. 4C. Examples of cleavage sites include: cleavage site for EK protease: DDDDK▾(SEQ ID NO: 9); cleavage site for Furin protease: RVRR▾ (SEQ ID NO: 10); cleavage site for Factor Xa protease: IEGR▾ (SEQ ID NO: 11); cleavage site for MMP protease: DIPEN▾FFG (SEQ ID NO: 12); and cleavage site for Aggrecanase: NITEGE▾ARGSVI (SEQ ID NO: 13).

Example 7. Sequences

Specific nucleotide and amino acid sequences may be utilized in embodiments of the invention.

Examples of primers useful for building HAB-IGF-I fusion protein constructs are provided in Table 4.

TABLE 4 Primers for building HAB-IGF-I fusion protein constructs SEQ Prim- ID er Sequence No. AG1 F 5′-GAATTCACCATGGCCACTTTACTCTGGGTTTTCGT 14 GACTC-3′ AG1 R 5′-GGGCCCGATGTCCACAAAGTCTTCACCTGTGTAG- 15 3′ LP F 5′-GAATTCACCATGGAGAGTCTACTTCTTCTGGTGCT 16 GATTTC-3′ LP R 5′-GGGCCCGTTGTATGCTCTGAAGCAGTAGACACC-3′ 17 VG1 F 5′-GAATTCACCATGGTCATAAATATAAAGAGCATCTT 18 ATGGA-3′ VG1 R 5′-GTCGAC CAATTGGATGACCAATTACACTCAAATCA 19 CTC-3′ IGF-I 5′-GTCGAC GGGCCCGAGACGCTCTGCGGGGCTGAGCT 20 F1 GGTG-3′ IGF-I 5′-CAATTGATTCAGAAGGACCGGAGACGCTCTGCGGG 21 F2 GCTGAG-3′ IGF-I 5′-CTCGAGCTACATCCTGTAGTTCTTGTTTCCTG-3′ 22 R IGF-I 5′-GAATTCACAATGGGAAAAATCAGCAGTCTTCC-3′ 23 F3 The underlined 6-bp sequence represents EcoR I (GAATTC), Xho I (CTCGAG), Mfe I (CAATTG), BamH I (GGATCC) or Apa I (GGGCCC) sites. Sal I (GTCGAC) site in primer VG1R and IGF-I F1I is included for cloning.

Human aggrecan gene nucleotide sequence is provided (SEQ ID No. 24) and the human aggrecan gene nucleotide sequence segment encoding the N-terminal 357 aa of human aggrecan (SEQ ID No. 25), which includes aggrecan G1 domain and a partial IGD domain (FIG. 1A). The aggrecan G1 domain (AG1) is responsible for the binding of aggrecan to hyaluronic acid.

Human aggrecan protein amino acid sequence is provided (SEQ ID No. 26) and the N-terminal 357 aa of human aggrecan (SEQ ID No. 27), which includes aggrecan G1 domain and a partial IGD domain (FIG. 1A). The aggrecan G1 domain (AG1) is responsible for the binding of aggrecan to hyaluronic acid.

Human link protein gene nucleotide sequence is provided (SEQ ID No. 28). Link protein (LP) binds to hyaluronic acid and aggrecan G1 domain (AG1) in stabilizing the interaction between aggrecan and hyaluronan to form aggrecan aggregates in articular cartilage.

Human link protein amino acid sequence is provided (SEQ ID No. 29).

Human versican gene nucleotide sequence is provided (SEQ ID No. 30) and the N-terminal 363 aa of human versican (SEQ ID No. 31), which includes versican G1 domain (FIG. 1A). The versican G1 domain (VG1) is responsible for the binding of versican to hyaluronic acid.

Human versican protein amino acid sequence is provided (SEQ ID No. 32) and the N-terminal 363 aa of human versican (SEQ ID No. 33), which includes versican G1 domain (FIG. 1A). The versican G1 domain (VG1) is responsible for the binding of versican to hyaluronic acid.

Human IGF-I (signal peptide and mature peptide and E peptide) gene nucleotide sequence is provided (SEQ ID No. 34). The 70aa gene nucleotide sequence encoding the IGF-I mature peptide (SEQ ID No. 35) is provided. The 48aa gene nucleotide sequence encoding the IGF-I signal peptide (SEQ ID No. 36) is provided. The 35aa gene nucleotide sequence encoding the IGF-I E peptide (SEQ ID No. 37) is also provided (FIG. 1A).

Human IGF-I (signal peptide and mature peptide and E peptide) protein amino acid sequence is provided (SEQ ID No. 38). The amino acid sequence (70aa) encoding the IGF-I mature peptide (SEQ ID No. 39) is provided. The amino acid sequence (48aa) encoding the IGF-I signal peptide (SEQ ID No. 40) is provided. The amino acid sequence (35aa) encoding the IGF-I E peptide (SEQ ID No. 41) is also provided (FIG. 1A).

HAB-IGF-I Fusion Protein

AG1-IGF-I fusion protein (FIG. 1B) nucleotide sequence is provided (SEQ ID No. 42). A segment of the AG1-IGF-I fusion protein nucleotide sequence encodes IGF-I mature peptide and E peptide (SEQ ID No. 43). This is fused to a c-terminal truncated aggrecan from AA 1 to AA 357, which includes aggrecan G1 domain (AG1) and a partial IGD domain. The aggrecan G1 domain (AG1) is responsible for the binding of aggrecan to hyaluronic acid.

AG1-IGF-I fusion protein (FIG. 1B) amino acid sequence is provided (SEQ ID No. 44). A segment of the AG1-IGF-I fusion protein amino acid sequence is IGF-I mature peptide and E peptide (SEQ ID No. 45). This is fused to a c-terminal truncated aggrecan from AA 1 to AA 357, which includes aggrecan G1 domain (AG1) and a partial IGD domain. The aggrecan G1 domain (AG1) is responsible for the binding of aggrecan to hyaluronic acid.

LP-IGF-I fusion protein (FIG. 1B) nucleotide sequence is provided (SEQ ID No. 46). A segment of the LP-IGF-I fusion protein nucleotide sequence encodes IGF-I mature peptide and E peptide (SEQ ID No. 47). This is fused to human link protein at c-terminal. Link protein (LP) binds to hyaluronic acid and aggrecan G1 domain (AG1) in stabilizing the interaction between aggrecan and hyaluronan to form aggrecan aggregates in articular cartilage.

LP-I1 (FIG. 1B) amino acid sequence is provided (SEQ ID No. 48). A segment of the LP-II amino acid sequence is IGF-I mature peptide and E peptide (SEQ ID No. 49). This is fused to human link protein at c-terminal. Link protein (LP) binds to hyaluronic acid and aggrecan G1 domain (AG1) in stabilizing the interaction between aggrecan and hyaluronan to form aggrecan aggregates in articular cartilage.

VG1-I1 (FIG. 1B) nucleotide sequence is provided (SEQ ID No. 50). A segment of the VG1-I1 nucleotide sequence encodes IGF-I mature peptide and E peptide (SEQ ID No. 51). This is fused to a c-terminal truncated versican from AA 1 to AA 363, which includes versican G1 domain (VG1). The versican G1 domain (VG1) is responsible for the binding of versican to hyaluronic acid.

VG1-I1 (FIG. 1B) amino acid sequence is provided (SEQ ID No. 52). A segment of the VG1-I1 sequence is IGF-I mature peptide and E peptide (SEQ ID No. 53). This is fused to a c-terminal truncated versican from AA 1 to AA 363, which includes versican G1 domain (VG1). The versican G1 domain (VG1) is responsible for the binding of versican to hyaluronic acid.

Human CD44 gene nucleotide sequence is provided (SEQ ID No. 54). The protein encoded by this gene sequence is a cell-surface glycoprotein. It is a receptor for hyaluronic acid (HA). This sequence (NM_0010013931) is one of CD44 mRNA splicing variants. The 5′-804 nt sequence (SEQ ID No. 55) encodes the N-terminal 268 aa of CD44: a signal peptide (SP) from AA1 to AA20 and an extracellular region from AA21 to AA268. The extracellular region from AA21 to AA268 contains the HA binding domain, which is responsible for the binding of CD44 to HA. The 60 nt sequence after the 804 nt sequence encodes the 20 aa of human CD44 transmembrane region (TM) (SEQ ID No. 56). The 3′-222 nt sequence encodes the 73 aa of the C-terminal intracellular region of CD44 (SEQ ID No. 57).

Human CD44 protein amino acid sequence is provided (SEQ ID No. 58). The N-terminal 268 aa sequence (SEQ ID No. 59) consists of a signal peptide (SP) from AA1 to AA20 and an extracellular region from AA21 to AA268. The CD44 extracellular region from AA21 to AA268 contains the HA-binding domain responsible for the binding of CD44 to HA. The C-terminal 73 aa sequence (SEQ ID No. 61) is the intracellular region of CD44. The 20 aa sequence between them is CD44 transmembrane region (TM) (SEQ ID No. 60) (FIG. 4A).

CD44-IGF-I Fusion Protein

CD44(132)-IGF-I nucleotide sequence is provided (SEQ ID No. 62). A segment of the CD44(132)-IGF-I nucleotide sequence (SEQ ID No. 63) encodes IGF-I mature peptide and E peptide. This is fused to a c-terminal truncated CD44 from AA 1 to AA 132 (FIG. 4B).

CD44(132)-IGF-I amino acid sequence is provided (SEQ ID No. 64). A segment of the CD44(132)-IGF-I amino acid sequence is IGF-I mature peptide and E peptide (SEQ ID No. 65). This is fused to a c-terminal truncated CD44 from AA 1 to AA 132 (FIG. 4B).

CD44(156)-IGF-I nucleotide sequence is provided (SEQ ID No. 66). A segment of the CD44(156)-IGF-I nucleotide sequence encodes IGF-I mature peptide and E peptide (SEQ ID No. 67). This is fused to a c-terminal truncated CD44 from AA 1 to AA 156 (FIG. 4B).

CD44(156)-IGF-I amino acid sequence is provided (SEQ ID No. 68). A segment of the CD44(156)-IGF-I amino acid sequence (SEQ ID No. 69) is IGF-I mature peptide and E peptide. This is fused to a c-terminal truncated CD44 from AA 1 to AA 156 (FIG. 4B).

CD44(178)-IGF-I nucleotide sequence is provided (SEQ ID No. 70). A segment of the CD44(178)-IGF-I nucleotide sequence encodes IGF-I mature peptide and E peptide (SEQ ID No. 71). This is fused to a c-terminal truncated CD44 from AA 1 to AA 178 (FIG. 4B).

CD44(178)-IGF-I amino acid sequence is provided (SEQ ID No. 72). A segment of the CD44(178)-IGF-I amino acid sequence encodes IGF-I mature peptide and E peptide (SEQ ID No. 73). This is fused to a c-terminal truncated CD44 from AA 1 to AA 178 (FIG. 4B).

CD44(222)-IGF-I nucleotide sequence is provided (SEQ ID No. 74). A segment of the CD44(222)-IGF-I nucleotide sequence encodes IGF-I mature peptide and E peptide (SEQ ID No. 75). This is fused to a c-terminal truncated CD44 from AA 1 to AA 222 (FIG. 4B).

CD44(222)-IGF-I amino acid sequence is provided (SEQ ID No. 76). A segment of the CD44(222)-IGF-I amino acid sequence is IGF-I mature peptide and E peptide (SEQ ID No. 77). This is fused to a c-terminal truncated CD44 from AA 1 to AA 222 (FIG. 4B).

Sequence Listing Table SEQ ID Abbreviation NO (as applicable) Name 1 Linker Linker 1 2 Linker Linker 2 3 Linker Linker 3 4 Linker Linker 4 5 Linker Linker 5 6 Linker Linker 6 7 Linker Linker 7 8 Linker Linker 8 9 Cleavage site cleavage site for EK protease 10 Cleavage site cleavage site for Furin protease 11 Cleavage site cleavage site for Factor Xa protease 12 Cleavage site cleavage site for MMP protease 13 Cleavage site cleavage site for Aggrecanase 14 AG1 F Primer: Aggrecan G1 domain (forward) 15 AG1 R Primer: Aggrecan G1 domain (reverse) 16 LP F Primer: Link Protein (forward) 17 LP R Primer: Link Protein (reverse) 18 VG1 F Primer: Versican G1 domain (forward) 19 VG1 R Primer: Versican G1 domain (reverse) 20 IGF-I F1 Primer: insulin-like growth factor (forward) 21 IGF-I F2 Primer: insulin-like growth factor (forward) 22 IGF-I R Primer: insulin-like growth factor (reverse) 23 IGF-I F3 Primer: insulin-like growth factor (forward) 24 Aggrecan Human aggrecan gene nucleotide sequence 25 nucleotide sequence N-terminal 357 aa of human aggrecan - includes aggrecan G1 domain (AG1) and a partial IGD domain 26 Aggrecan Human aggrecan protein amino acid sequence 27 amino acid sequence N-terminal 357 aa of human aggrecan 28 LP Human link protein gene nucleotide sequence 29 LP Human link protein amino acid sequence 30 Versican Human versican gene nucleotide sequence 31 nucleotide sequence N-terminal 363 aa of human versican - includes versican G1 domain (VG1) 32 Versican Human versican protein amino acid sequence 33 amino acid sequence N-terminal 363 aa of human versican - includes versican G1 domain (VG1) 34 Human IGF-I (signal peptide and mature peptide and E peptide) gene nucleotide sequence 35 IGF-I (70aa) IGF-I mature peptide nucleotide sequence 36 SP IGF-I signal peptide nucleotide sequence 37 E peptide IGF-I E nucleotide sequence 38 Human IGF-I (signal peptide, mature peptide, and E peptide) amino acid sequence 39 IGF-I (70aa) IGF-I mature peptide amino acid sequence 40 SP IGF-I signal peptide amino acid sequence 41 E peptide IGF-I E peptide amino acid sequence 42 AG1-IGF-I fusion protein nucleotide sequence 43 segment of the AG1-IGF-I fusion protein nucleotide sequence encoding IGF-I mature peptide and E peptide 44 AG1-IGF-I fusion protein amino acid sequence 45 segment of the AG1-IGF-I fusion protein amino acid sequence: IGF-I mature peptide and E peptide 46 LP-IGF-I fusion protein nucleotide sequence 47 segment of the LP-IGF-I fusion protein nucleotide sequence encoding IGF-I mature peptide and E peptide 48 LP-I1 amino acid sequence 49 segment of the LP-I1 amino acid sequence: IGF-I mature peptide and E peptide 50 VG1-IGF-1 nucleotide sequence 51 segment of the VG1-IGF-1 nucleotide sequence encoding IGF-I mature peptide and E peptide 52 VG1-IGF-1 amino acid sequence 53 segment of the VG1-IGF-1 nucleotide sequence: IGF-I mature peptide and E peptide 54 CD44 Human CD44 gene nucleotide sequence 55 N-terminal 268 aa of CD44 (including SP & HAB) 56 TM human CD44 transmembrane region 57 C-terminal intracellular region of CD44 58 Human CD44 protein amino acid sequence 59 CD44 N-terminal 268 aa sequence consists of a signal peptide (SP) from AA1 to AA20 and an extracellular region from AA21 to AA268 60 CD44 transmembrane region 61 C-terminal intracellular region of CD44 62 CD44(132)-IGF-I nucleotide sequence 63 segment of the CD44(132)-IGF-I nucleotide sequence encoding IGF-I mature peptide and E peptide 64 CD44(132)-IGF-I amino acid sequence 65 segment of the CD44(132)-IGF-I amino acid sequence is IGF-I mature peptide and E peptide 66 CD44(156)-IGF-I nucleotide sequence 67 segment of the CD44(156)-IGF-I nucleotide sequence encodes IGF-I mature peptide and E peptide 68 CD44(156)-IGF-I amino acid sequence 69 segment of the CD44(156)-IGF-I amino acid sequence: IGF-I mature peptide and E peptide 70 CD44(178)-IGF-I nucleotide sequence 71 segment of the CD44(178)-IGF-I nucleotide sequence encoding IGF-I mature peptide and E peptide 72 CD44(178)-IGF-I amino acid sequence 73 segment of the CD44(178)-IGF-I amino acid sequence: IGF-I mature peptide and E peptide 74 CD44(222)-IGF-I nucleotide sequence 75 segment of the CD44(222)-IGF-I nucleotide sequence encoding IGF-I mature peptide and E peptide 76 CD44(222)-IGF-I amino acid sequence 77 segment of the CD44(222)-IGF-I amino acid sequence: IGF-I mature peptide and E peptide

The terms and expressions which have been employed are used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof. Thus, it should be understood that although the present invention has been specifically disclosed by particular embodiments and optional features, modification and variation of the concepts herein disclosed may be used by those skilled in the art, and that such modifications and variations are considered to be within the scope of this invention as defined by the appended claims. Whenever a range is given in the specification, all intermediate ranges and subranges, as well as all individual values included in the ranges given are intended to be included in the disclosure. When a Markush group or other grouping is used herein, all individual members of the group and all combinations and sub-combinations possible of the group are intended to be individually included in the disclosure. While the present invention has been described in terms of those particular embodiments and examples, it will be appreciated that the spirit and scope of the invention is not limited to those embodiments, but extends to the various modifications and equivalents as defined in the appended claims. 

We claim:
 1. A fusion protein, comprising: a.) a hyaluronic acid-binding domain (HAB) of a cartilage matrix protein linked to b.) a conserved region of a growth factor (GF) protein, wherein said fusion protein is capable of upregulating glycosaminoglycan (GAG) expression in chondrocytes.
 2. The fusion protein of claim 1, which further comprises at least one additional element selected from the group consisting of: signal peptide (SP); linker peptide (linker); protease cleavage site; E peptide; and additional functional peptide.
 3. The fusion protein of claim 2, wherein the order of elements, N-terminus to C-terminus is: SP-HAB-GF-E peptide.
 4. The fusion protein of claim 2, wherein the order of elements, N-terminus to C-terminus is selected from the group consisting of: SP-HAB-GF; SP-HAB-GF-E peptide; SP-HAB-GF-additional peptide sequence; SP-HAB-linker-GF-additional peptide sequence; SP-HAB-linker-GF-E peptide; SP-HAB-linker-protease cleavage sequence-GF-additional peptide sequence; and SP-HAB-linker-protease cleavage sequence-GF-E peptide.
 5. The fusion protein of claim 2, wherein the SP is selected from the group consisting of: aggrecan signal peptide, CD44 signal peptide; link protein signal peptide; TSG-6 signal peptide, versican signal peptide; and other HA-binding protein signal peptide.
 6. The fusion protein of claim 1, wherein the HAB is selected from the group consisting of: aggrecan; CD44; link protein; TSG-6; versican; and other HA-binding proteins.
 7. The fusion protein of claim 2, wherein the linker is selected from the group consisting of: Linker 1: GGSG (SEQ ID NO: 1); Linker 2: GGSGGGSG (SEQ ID NO: 2); Linker 3: GGSGGGSGGGSG (SEQ ID NO: 3); Linker 4: GGGGS (SEQ ID NO: 4); Linker 5: GGGGSGGGGS (SEQ ID NO: 5); Linker 6: GGGGSGGGGSGGGGS (SEQ ID NO: 6); Linker 7: GGSGGS (SEQ ID NO: 7); and Linker 8: VIGHPIDSE (SEQ ID NO: 8).
 8. The fusion protein of claim 2, wherein the protease cleavage site is selected from the group consisting of: SEQ ID NO: 9; SEQ ID NO: 10; SEQ ID NO: 11; SEQ ID NO: 12; and SEQ ID NO:
 13. 9. The fusion protein of claim 1, wherein the GF is selected from the group consisting of: IGF-1; BMP2; BMP4; BMP7; FGF2; FGF18; GDF5; TGF-β1 and TGF-β3
 10. The fusion protein of claim 1, wherein the CD44 HAB element is a polypeptide having at least 90 percent identity to a polypeptide selected from the group consisting of: amino acids 1-132 of SEQ ID NO: 64; amino acids 1-156 of SEQ ID NO: 68; amino acids 1-178 of SEQ ID NO: 72; and amino acids 1-222 of SEQ ID NO:
 76. 11. The fusion protein of claim 1, further comprising: flanking amino acids to the HAB, wherein the number of flanking amino acids is selected from the group consisting of: 5 amino acids; 10 amino acids; 15 amino acids; 20 amino acids; 25 amino acids; 30 amino acids; 35 amino acids; 40 amino acids; 45 amino acids; 50 amino acids; 55 amino acids; and 60 amino acids.
 12. The fusion protein of claim 11, wherein the flanking amino acids are at the N terminus of HAB.
 13. The fusion protein of claim 11, wherein the flanking amino acids are at the C terminus of HAB.
 14. A nucleic acid molecule comprising a nucleic acid sequence that encodes a fusion protein comprising: a.) a hyaluronic acid-binding domain of a cartilage matrix protein (HAB) operably linked to b.) a conserved region of a growth factor protein (GF), wherein said fusion protein is capable of up-regulating glycosaminoglycan (GAG) expression in chondrocytes.
 15. The nucleic acid molecule of claim 14, wherein the nucleic acid molecule further comprises at least one additional nucleic acid sequence, wherein the additional nucleic acid sequence is selected from the group consisting of: a nucleic acid sequence that encodes at least one signal peptide (SP); a nucleic acid sequence that encodes at least one linker sequence (linker); a nucleic acid sequence that encodes at least one protease cleavage sequence; a nucleic acid sequence that encodes at least one E peptide; and a nucleic acid sequence that encodes at least one additional functional peptide; wherein the nucleic acids are operably linked so as to express a functional fusion protein.
 16. The nucleic acid molecule of claim 15, wherein the order of operably-linked elements, 5′ to 3′ is selected from the group consisting of: SP-HAB-GF; SP-HAB-GF-additional functional peptide; SP-HAB-GF-E peptide; SP-HAB-linker-GF-additional functional peptide; SP-HAB-linker-GF-E peptide; SP-HAB-linker-protease cleavage sequence-GF-E peptide; and SP-HAB-linker-protease cleavage sequence-GF-additional functional peptide.
 17. The nucleic acid molecule of claim 15, wherein the SP is selected from the group consisting of: aggrecan signal peptide; CD44 signal peptide; link protein signal peptide; TSG-6 signal peptide; versican signal peptide; and other HA-binding protein signal peptide.
 18. The nucleic acid molecule of claim 14, wherein the HAB comprises a polynucleotide fragment of a nucleotide sequence encoding a protein selected from the group consisting of: aggrecan; CD44; link protein; TSG-6; versican; and other HA-binding proteins.
 19. The nucleic acid molecule of claim 15, wherein the linker is selected from the group consisting of: Linker 1: GGSG (SEQ ID NO: 1); Linker 2: GGSGGGSG (SEQ ID NO: 2); Linker 3: GGSGGGSGGGSG (SEQ ID NO: 3); Linker 4: GGGGS (SEQ ID NO: 4); Linker 5: GGGGSGGGGS (SEQ ID NO: 5); Linker 6: GGGGSGGGGSGGGGS (SEQ ID NO: 6); Linker 7: GGSGGS (SEQ ID NO: 7); and Linker 8: VIGHPIDSE (SEQ ID NO: 8).
 20. The nucleic acid molecule of claim 15, comprising a cleavage site for a protease selected from the group consisting of: enterokinase (EK); Furin; Factor Xa; Matrix metalloproteinase (MMP); and Aggrecanase.
 21. The nucleic acid molecule of claim 14, wherein the GF is selected from the group consisting of: IGF-1; BMP2; BMP4; BMP7; FGF2; FGF18; GDF5; TGF-β1; and TGF-β3.
 22. The nucleic acid molecule of claim 14, wherein the HAB element comprises a sequence that is at least 80% identical to at least one sequence selected from the group consisting of: nucleotides 1-222; 1-178; 1-156; and 1-132 of SEQ ID NO:
 54. 23. The nucleic acid molecule of claim 14, wherein the nucleic acid molecule encodes a fusion protein comprising HAB and IGF-1 linked by a number of amino acids selected from the group consisting of: at least about 60 amino acids, at least about 50 amino acids, at least about 40 amino acids, at least about 30 amino acids, at least about 20 amino acids, fewer than 20 amino acids; fewer than 15 amino acids; fewer than 10 amino acids; fewer than 5 amino acids; no amino acids.
 24. A composition comprising the nucleic acid molecule of claim 14 and a pharmaceutically-acceptable carrier.
 25. A composition comprising the fusion protein of claim 1 and a pharmaceutically-acceptable carrier.
 26. An expression vector encoding the fusion protein of claim 1, wherein the expression vector is a plasmid or a virus.
 27. The expression vector of claim 26, which is an adeno-associated virus plasmid (pAAV).
 28. A cell transformed, transfected, or transduced by a vector of claim
 26. 29. The cell of claim 28, wherein the cell is a chondrocyte.
 30. An animal model comprising the cell of claim
 28. 31. A method of producing a fusion protein comprising, expressing a nucleic acid molecule in the cell of claim
 28. 32. A method to upregulate glycosaminoglycan expression in at least one chondrocyte, comprising: expressing a nucleic acid molecule in at least one chondrocyte, wherein the nucleic acid molecule comprises a HAB element and a GF element.
 33. The method of claim 32 wherein the nucleic acid molecule comprises at least one segment having at least 95% identity to a sequence selected from the group consisting of: SEQ ID NO: 28; SEQ ID NO: 35; SEQ ID NO: 37; SEQ ID NO: 42; SEQ ID NO: 46; SEQ ID NO: 50; SEQ ID NO: 62; SEQ ID NO: 66; SEQ ID NO: 70; and SEQ ID NO:
 74. 34. A method to treat a cartilage matrix protein-related pathology or injury in a subject, comprising: administering a fusion protein, wherein the fusion protein comprises: a.) a hyaluronic acid-binding domain (HAB) of a cartilage matrix protein linked to b.) a conserved region of a growth factor (GF) protein, wherein the fusion protein is capable of upregulating glycosaminoglycan (GAG) expression in chondrocytes; upregulating GAG expression in chondrocytes in the subject; and treating a cartilage matrix protein-related pathology or injury.
 35. The method of claim 34 wherein the GF is IGF-I.
 36. The method of claim 34 wherein the administering is performed by transforming at least one chondrocyte in vivo to express the fusion protein.
 37. The method of claim 34 wherein the administering is performed by injection of a pharmaceutical composition comprising the fusion protein, wherein the fusion protein is produced in vitro.
 38. The method of claim 34, wherein the cartilage matrix protein-related pathology or injury is selected from the group consisting of: joint stiffness; joint pain; intervertebral disc pain; degenerative disease; facet disease; traumatic cartilage injury; surgical cartilage injury; osteoarthritis; and rheumatoid arthritis.
 39. The method of claim 34 further comprising: increasing sports performance in the subject, wherein the sports performance is selected from the group consisting of: increased speed; increased endurance; increased weight-lifting ability; increased flexibility; increased strength; increased resistance to impact; increased concentration; and increased career length.
 40. The method of claim 34 further comprising: decreasing GF removal rate from the joint synovium or intervertebral disc synovium of a subject, by introducing the fusion protein to at least one joint or intevertebral disc of a subject and decreasing GF removal rate from the joint synovium or intervertebral disc of the subject.
 41. The method of claim 34 further comprising: increasing responsiveness rates of chondrocytes to GF in a subject, by introducing the fusion protein to at least one chondrocyte of a subject and increasing responsiveness rates of chondrocytes to GF in the subject. 